This invention relates to a method for operating an air conditioner, and, more particularly, to a method of operation wherein, even upon a trouble wire disconnection of short-circuit may in any of the sensors detecting various operation control parameters required for the operation of the air conditioner, another normal sensor which has a complementary relation with the disabled sensor with respect to the heat cycle or which has an object of measurement substantially the same as that of the disabled sensor is substituted for the purpose of measurement, so that the air conditioner can continuously be operated without stopping.
As is well known, an air conditioner is basically composed of an outdoor unit and an indoor unit, and a plurality of sensors are respectively provided for the outdoor and indoor units. The operation of the air conditioner is controlled on the basis of values measured by these sensors.
In a modern air conditioner, a variety of functions are required together with an improvement in the amenity of air conditioning, and, to meet this requirement, the number of the sensors is being increased. This means that the probability of occurrence of wire disconnection, short-circuit or similar problem in the sensors increases, and measures for dealing with such sensor problems are now demanded. There are various prior art publications concerning such countermeasures. According to "Free Service Manual for Hitachi's Building Air Conditioner Himul Set, No. PAH-8802, pp. 3-37 to 3-44", the operation of an air conditioner is stopped in the event of occurrence of trouble in any one of sensors, the detail of the sensor trouble is coded and displayed. Also, according to JP-A-60-69444, when a control part in an indoor unit of an air conditioner is disabled, a signal for forcibly operating a compressor in an outdoor unit is applied from the indoor unit so as to forcibly operate the compressor in the outdoor unit.
Thus, the prior art practices are merely such that, when a sensor is disabled, the sensor trouble is displayed, and the operation of the air conditioner is stopped, or, when the indoor control part is disabled, the compressor in the outdoor unit is forcibly operated. Therefore, in prior art, the normal operation control of the air conditioner cannot be continued when any one of the sensors is disabled.